So, the problem isn't a bug, it's the intended (but perhaps incorrectly so) behavior. The search looks for players whose current bid is between 60% and 80% of your available funds (money - bids).
If you keep it that way, then I think it would be wise to present this information clearly somewhere to the end user. There's no way I would have expected it to only consider that range by default... from the outside, it appears badly broken.
I personally don't think you should keep it that way. Anything up to 100% sounds reasonable to me, with the nearest expiring auction being presented when there are multiple matches. Actually, maybe any match at all regardless of cost, perhaps with a toggle in the preferences for suppressing players you can't currently afford. But I'm not your Product Manager.